Field of the Invention
The present invention relates to a skateboard, and more particularly, to a skateboard which is capable of providing a self-propulsive force and is configured such that a skateboard is propelled by a user's action of repeating spreading and closing movement of his or her feet while putting his or her feet on a footrest installed on a board main body, it is easy to reduce risk of the safety accident and maintain balance, and it is possible to achieve an increase in a moving speed of the skateboard and change a travelling direction of the skateboard to an opposite direction if necessary.
Description of the Related Art
Generally, a skateboard is a type of sports equipment which includes an elongated plate and four wheels attached to the front and rear sides of the elongated plate and is propelled by kicking the ground with one foot. Particularly, the skateboard is a type of play equipment which allows a user to slide down a hill or the like while putting his or her feet on the skateboard.
In other words, the skateboard includes a long elliptical plate and two wheel assemblies on the bottom of the plate. Each of the wheel assemblies has two rollers. According to the related art, in the case of skateboarding on a flatland, the skateboard is propelled by a propulsive force generated when a user kicks the ground with one foot. The user can enjoy skateboarding in such a manner that the user turns the skateboard during skateboarding by tilting the skateboard to a left or right side with respect to a travelling direction of the skateboard with his or her foot or by leaning his or her body.
When the user rides such a skateboard, there is an inconvenience in that the user has to repeatedly kick the ground with one foot while the other foot is put on the skateboard so as to obtain a propulsive force.
In other words, since the user has to repeatedly kick the ground with one foot so as to obtain a continuous propulsive force, the user has to maintain his or her balance with the other foot. Consequently, the balance is easily broken, and thus, risk of the safety accident is high. Furthermore, when the user kicks the ground, the user has to push the ground while continuously moving one foot up and down, and thus, the user easily gets tired.
In addition, when the user rides the skateboard, the user kicks the ground with one foot while the other foot supports the user's body. Therefore, it is difficult for the user to maintain his or her balance when the user kicks the ground or when the user puts one foot on the plate of the skateboard after kicking the ground. Thus, there is a problem in that unskilled persons cannot ride the skateboard.
Moreover, as for the skateboard according to the related art, since the user kicks the ground with one foot while the other foot supports the user, as described above, a speed of the skateboard on a flatland is limited in a certain range (for example, about 10 km to about 15 km). As a result, there is a limitation in enjoying skateboarding at higher speed.